1. Field of the Invention
The invention relates to a magnetic resonance device, comprising a main field magnet for generating a steady magnetic field in a measurement space for accommodating an object, a coil system for generating a gradient magnetic field, an RF coil system for generating RF electromagnetic pulses, and sampling means for sampling magnetic resonance signals generated in the object, which device furthermore comprises control means and also shimming means for shimming the steady magnetic field.
2. Description of the Related Art
A magnetic resonance device of this kind is known from U.S. Pat. No. 4,987,371. That US Patent describes a shimming method which is based on an inhomogeneity map of the main field which is determined from phase measurements of each voxel in the object. First two images of a slice of the object are determined by memos of a so-called spin echo or a so-called spin-warp measuring sequence, the timing of the echo resonance signal for the different images being chosen so as to be different. Subsequently, a ratio image is determined from said two images and finally, after multiplication of the ratio image by a weighting function, shimming gradients are determined by way of curve fitting. This enables linear and higher-order shimming. This shimming method is cumbersome and time-consuming.